Lucky Black Dog Meets Mickey.
This is pretty interesting. There is a very old pre WWII Japanese cartoon featuring a soldier in the Dog army named のらくろ or Lt. Norakuro.
In the original story, Norakuro was a soldier serving in an army of dogs, in the 'fierce dogs brigade' (猛犬連隊, mōkenrentai). The story began in 1931, and was clearly based on the Japanese Imperial army of the time. The artist, Suihō, had served in the Imperial army from 1919 to 1922. Norakuro is gradually promoted from private to sergeant in the stories, which are humorous episodes. (From Wiki)
Here's one of the cartoons from the 30s.
Mickey Mouse makes an early cameo and meets Norakuro in an early anime called (roughly translated) 2nd Class Lt. Norakuro and Mickey Mouse Play Disturbance. It's all part of the Toyfilm Project which is documenting all these old tunes. Scroll down and in addition to Mickey, you'll see pics of Pluto, Betty Boop, Popeye and even Porky Pig.
Norakuro stopped production after The Big One, but picked up production in 1970-71 and 1987-88 (starring the voice of Doraemon.)
Pretty cool stuff, eh? (Thanks to Cartoon Brew for the heads up.)